Typical PS-1 diesel have interior and number board lights off the CV Board and they are 6V bulbs. You might have a track power bulb at 18V. BUT directional Headlights are powered off the PS-1 board and they are 1.5V bulbs and will not work with TMCC.
Any light you are power off the TMCC board needs to be a 16-18V bulb or an LED with appropriate resistor.
Markers are markers and PS-1 are parallel wired while PS-2/3 are series wired. Follow normal resistor values base on TMCC voltage or track power.
PS-1 could be off the CV with a 150ohm resistor, or they could be directly off the PS-1 marker plug which has built in resistor.
Just normal lighting stuff. Match it to how Lionel engines are wired, or leave the MTH CV stuff alone as normal. G
